The objective of the study is to examine whether the potential public health impact on coronary heart disease (CHD) risk reduction of an NCEP/AHA Step One Diet may currently be underestimated because of an overemphasis on the avoidance of fat and cholesterol and an underemphasis on the inclusion of plant-based foods. A large number of dietary factors in plant based foods have been linked to the reduction of various CHD risk factors. However, the food industry's production of thousands of new "reduced-fat" food products over the last decade has now made it possible to follow a Step One Diet with a foundation in low-fat commercial foods (that are often high in calories) rather than plant-based foods. We will design two diets that both meet NCEP/AHA Step One Diet guidelines and are matched on total fat, saturated fat, monounsaturated fat, polyunsaturated fat, cholesterol, protein and total carboyhydrate. One diet will include a large proportion of plant-based foods, and will be relatively higher in content of plant protein, arginine, complex carbohydrates, soluble and insoluble fiber, Vitamins E, C and folate, carotenoids, phytosterols, phytoestrogens, flavonoids, allicin and saponins (NCEP-Plus). The other diet will include a large proportion of commercially available reduced-fat products and will be relatively higher in animal protein, simple carbohydrates and trans fatty acids (NCEP-Low).